1. Field of the Invention
The invention relates to paper handling systems, and more particularly to paper handling systems used in combination with duplicating machines for receiving printed sheets in serial paginated sequence and presenting the sheets in a finished stack of bound pamphlets.
2. Prior Art
In many office environments, it is necessary to augment a duplicating machine with additional equipment which processes the output of the duplicating machine. For example, it is often necessary to collect the paper output of a duplicating machine into stacked sets of sheets, bind the sheets of each set together into pamphlets by staples or other means, then stack the pamphlets in a suitable fashion for presentation to a user. In the typical prior art duplicating system the printed sheets are produced in common page sets which must be collated by appropriate collation means prior to binding into pamphlet form. Recently, however, advances in the data processing field have made it possible to scan and load entire multi page documents into memory and to perform collation electronically. A duplicator which is equipped for electronic collation prints pamphlet pages in serial sequence. Thereafter the pages must be collected into pamphlet defining sets and suitably bound. Ink jet printers and electrostatic printers of many types are suitable for use in such an application.
Many devices have been developed to collect, bind, and stack the sheet output from a duplicating machine. For example, U.S. Pat. No. 3,265,274 is directed to a pamphlet assembly and stapling machine. A collator feeds sheets onto downwardly inclined conveyor belts which deposit them on a horizontally running belt system. The horizontally running belts include pairs of upwardly extending pins which engage the trailing edges of the individual sheets as they are carried on the belt. The sheets pass beneath a cover feed station in which a vacuum assembly places a relatively rigid cover upon the sheets as they pass beneath. The sheets then are urged against stops where they are collected into a set and bound into pamphlets by a stapling machine. The pamphlets are then transported to a folding machine which ultimately deposits them on a downwardly inclined receiving platform.
A disadvantage with this device is that the various components of the system are arranged linearly and on about the same plane. Therefore, the device requires a large amount of horizontal space. This factor reduces the capability of such a device to be utilized in a standard office environment. In addition, the downwardly inclined tray of the device does not provide a surface upon which pamphlets may be stacked in an offset fashion. Rather, the pamphlets lie upon the tray in a shingled, overlapping relationship, making it difficult to transport them in bulk to another station by a user.
Another example of a paper handling system is disclosed in U.S. Pat. No. 3,685,712. This patent is directed to a stapling apparatus in which sheets are received serially from a duplicating machine and deposited on a tray forming a portion of a receiving tray assembly. The sheets are urged against a gate mounted to the lid above the tray and are collected there into sets. The sets are bound into pamphlets on the tray and then conveyed to a downwardly inclined tray which indexes downwardly as successive pamphlets are deposited upon it.
This type of device possesses several disadvantages. The collecting mechanism is complicated, requiring flexible paddle wheels to orient the sheets in a stacked relation prior to stapling. The device includes an offset stacking apparatus mounted in the lid which presents problems in the construction and orientation of the offset stacking apparatus requiring close tolerances to assure proper registration of the lid above the tray supporting the finished pamphlets. Furthermore, the tray supporting the finished pamphlets which indexes downwardly must be unloaded from the top requiring the user to reach over the sides of the apparatus and lift out the stacked pamphlets, after opening the lid of the apparatus, which exposes the interior components to external sources of pollution and entanglement with clothing or hair of the user.
Accordingly, there is a need for a paper handling system in which paper sheets are collected into sets by an accumulator, the sets are transported to a finishing station where they are bound into pamphlets, then to a stacking station where they are stacked either uniformly or offset, and then to a discharge station where the stack is presented to a user at an optimum elevation which obviates the need for reaching inside an enclosure to remove the stack. In addition, the components of each portion of the paper handling system must be of simplified construction to eliminate high costs of manufacturing and the need for parts having close tolerances. There is also a need for a system which possesses desirable height, width, and length dimensions making it suitable for placement in a conventional office environment.